Selective screening or filtering of traffic is a useful tool in a computer network environment. When properly configured, for example, filtering traffic can prevent access to inappropriate content, focus the scope of content accessible by a public or work computer, or reduce the risk of exposure to a computer virus or online fraud scheme.
Broadly speaking, network traffic filtering approaches generally operate by intercepting requests from an application, such as Web browser. These requests are then vetted with reference to a filtering policy, often with further reference to a centralized authentication service. If the request is allowable under the local policy, the application is allowed to proceed with the network request; if the request is not allowed, the application may be redirected to an informative message, indicating that the requested content cannot be accessed under the current policy.
Often, existing traffic filtering approaches will include a logging functionality, which records the requests issued by the applications being monitored. These logs can then be examined to determine what requests have been made, as well as what content has been accessed.